A bump on the back of the head has many possible causes, including injuries, cysts, fatty growths, inflamed hair follicles, and more. The cause and the symptoms a person experiences will determine the best treatment.

Injuries are a common cause of bumps and lumps on the back of the head. Forceful blows to the head can lead to brain injury, so a person must watch for symptoms of concussion. People with a concussion or another severe head injury should seek medical attention.

Some other causes of bumps on the back of the head may also require a person to contact a doctor.

This article explores some possible causes of a bump on the back of the head. It also explains when to speak with a doctor.

Injury can cause a bump on the back of the head. Possible causes of head injuries to this area include:

  • falling backward
  • impacts or collisions during contact sports
  • violence
  • hitting the head against the headrest of a car seat in a traffic accident
  • other types of accident

A blow to the back of the head can cause a scalp hematoma, which is where a collection of blood just beneath the skin forms a semisolid bump. People sometimes refer to these bumps as “goose eggs.”


People can usually treat minor head injuries at home with rest, over-the-counter pain relievers, and ice packs.

However, more serious injuries can cause a concussion. A severe concussion can lead to dangerous complications if a person does not receive treatment.

The symptoms of concussion can include:

People with symptoms of concussion should seek immediate medical attention.

Anyone who has hit their head very hard or been in a severe accident should go to the emergency room even if they do not yet have symptoms of concussion. A doctor can perform tests to rule out a concussion and other brain injuries.

Pilar cysts are skin cysts that usually develop on a person’s scalp but can also occur on the neck. Doctors sometimes refer to pilar cysts as trichilemmal cysts.

These cysts are smooth, dense lumps containing a buildup of keratin, the protein the body uses to make hair and nails. Pilar cysts usually grow slowly, typically varying between several millimeters and a few centimeters in diameter.

Pilar cysts are more common in females than in males and can sometimes run in families.


Pilar cysts are generally harmless and asymptomatic but can sometimes be painful.

If a cyst is not causing symptoms, treatment may not be necessary. However, if a pilar cyst causes discomfort or other problems, a doctor may recommend surgically removing it.

A lipoma is a soft, fatty growth that can develop underneath the skin. Lipomas can occur anywhere on the body, including the back of the head and neck.

These bumps can vary in size, but they are not usually painful. A lipoma will typically feel soft and rubbery and may move around when a person presses down on it.

Doctors do not fully understand what causes lipomas, but they occur most often in people ages 40–60 years and are slightly more common in males than in females.


Lipomas are generally harmless and usually do not require treatment. However, if a lipoma becomes very large or is causing a person problems, a doctor may recommend surgical removal.

Doctors may also suggest removal if they are uncertain whether the bump is a lipoma.

A bone spur, or exostosis, is a bony outgrowth that can develop around a joint. Bone spurs may grow in the:

  • neck
  • knee
  • shoulder
  • lower back
  • foot or heel
  • fingers
  • big toe

Bone spurs feel like hard, immovable lumps. Although not always tender, these growths may cause pain if they rub against or put pressure on bones, tissues, or nerves.

They can develop near the affected joints in people with osteoarthritis. Osteoarthritis causes degenerative changes in the cartilage and bone in the joints, where bone spurs form during the process.


Bone spurs do not usually require intensive treatment. If they are causing a person pain or other problems, a doctor may recommend:

In some cases, they may advise surgery to remove the bone spur.

Acne develops when the hair follicles become clogged with a buildup of skin cells and sebum, an oily, waxy substance. As the scalp has many hair follicles, acne can also develop on the scalp and around the hairline.

The American Academy of Dermatology Association notes that some hair care products can also cause scalp acne.


Although the acne can resolve without treatment, some people may require medicated products.

Learn more about how to treat and prevent scalp acne.

Scalp folliculitis is a condition in which hair follicles on the scalp become inflamed. The inflammation can cause a pus-filled bump that may resemble a pimple and can grow larger.

The symptoms of folliculitis can include:

  • itching
  • inflammation
  • soreness
  • a white head on top of the bump

Infection may occur in the affected follicles.


At home, people can apply a warm compress to help reduce inflammation and drain the pus. They can also apply an antibiotic ointment and wash their hair with anti-dandruff shampoo.

A doctor may recommend oral antibiotics or prescription creams or ointments for people with more severe scalp folliculitis.

An ingrown hair occurs when a hair that cannot grow out correctly grows back under the skin instead.

If hairs become ingrown, they can cause raised, inflamed, itchy spots on the skin. These may occur if a person shaves their head. They are more likely to occur in people with curly hair.


Most ingrown hairs will resolve without treatment, but a doctor may prescribe antibiotics if an infection develops. To minimize the risk of infection, people should avoid picking at the ingrown hair.

Learn more about how to deal with an ingrown hair.

An epidermoid cyst is a benign cyst consisting of cheese-like keratin inside a distinct sac wall. These cysts are typically not cancerous.

Epidermoid cysts often have a visible punctum, which is a small central opening. They are the most common type of cutaneous cyst.


A dermatologist may be able to remove the cyst. If they manage to remove it in whole, with the sac wall intact, it is unlikely to grow back.

In rare instances, a bump on the back of the head can be a bone tumor.

One of the more common types of cervical spine tumors is a chordoma, which is a tumor that can grow from the bones at the base of the skull. However, in comparison with all bone cancer types, a chordoma is rare.

Small chordomas typically do not cause noticeable symptoms. However, the symptoms of larger chordomas may include:

  • walking and balance difficulties
  • headaches
  • hearing problems
  • visual disturbances

Chordomas can spread to other parts of the body.


The treatment for a skull bone tumor will depend on multiple factors, including:

  • whether the tumor is benign or cancerous
  • the size of the tumor
  • the location of the tumor cells
  • other individual variables

It is important to contact a doctor if the bump on the back of the head:

  • seems to be getting larger or is worsening
  • causes severe pain or other problems
  • produces pus or discharge
  • is warm to the touch, or the surrounding area is discolored

People who have been in a serious accident or sustained a severe head injury should go to the emergency room.

It is also important to seek immediate medical attention if any of the following symptoms occur following a head injury:

  • loss of consciousness, lethargy, or seizures
  • dizziness
  • persistent vomiting
  • clear or bloody discharge coming from the ears or nose
  • different sized pupils in the eyes
  • slurred speech, confusion, or memory loss
  • balance or walking difficulties

Below are some common questions about a lump on the back of the head.

Can a lump on the back of the head be cancerous?

In very rare cases, a lump on the back of the head can occur due to bone cancer. However, causes like cysts or injury are more common. People should speak with a doctor for a proper diagnosis.

Should someone worry about a head bump?

A bump on the head is not always a cause for concern. However, people should seek immediate medical help if they experience other symptoms, such as vision changes, changes in consciousness, or slurred speech.

What is a hard lump on the head feels like a bone?

A hard lump on the head could be due to bone spurs, which are bony lumps that most often grow around joints.

Injuries are a common cause of bumps on the back of the head. People can usually treat mild head injuries at home. However, people with severe head injuries or symptoms of concussion should seek immediate medical attention.

Other causes of bumps on the back of the head can include cysts, fatty growths, acne, inflamed hair follicles, epidermoid cysts, and bone spurs.

People should contact a doctor about any bump that is causing problems or seems to be getting larger or worse.